The formulation of pipeline-transportable crude oil-in-water emulsion can not generally be formulated by combining emulsifying agent(s) directly with produced hydrocarbon crude, and subsequently agitating with a dynamic mixer the mixture of produced hydrocarbon crude and emulsifying agent(s). The emulsifying agent(s) is not soluble in oil and is only soluble in an aqueous solution. By contacting directly the produced hydrocarbon crude with the emulsifying agent(s) without premixing the emulsifying agent(s) with water, brine, or the like, diffusion of the emulsifying agent(s) through the produced hydrocarbon crude to the oil/water interface is slow; and with some produced hydrocarbon crudes, such as Athabasca bitumen from the Athabasca tar sands in the province of Alberta, Canada, oil-in-water emulsion(s) can not be formulated. Also, through the use of a dynamic mixer, such as the rotor-stator mixer, not every produced hydrocarbon crude can be emulsified into a water continuous emulsion, even with premixing the emulsifying agent(s) with water prior to combining with produced hydrocarbon crude. A high shear field cannot be obtained with a dynamic mixer unless the mixture of produced hydrocarbon crude and emulsifying agent(s) (including any water solvent) makes numerous passes through the dynamic mixer. Transport oil-in-water emulsion(s) is shear-sensitive, and a dynamic mixer tends to cause either an overshear-damaged product or less than a perfectly mixed product, depending on the mixing severity employed with the dynamic mixer.
Large storage tanks and/or mixing tanks are generally required when utilizing dynamic mixers. If a dynamic mixer is separate from the storage tank, mixtures to be emulsified have to be recirculated from the storage tank, through the mixer, and back into the storage tank. The degree of mixing achieved by dynamic mixers depends on the mixing speed, impeller design, impeller position, length of mixing time, tank volume, tank geometry, etc. Dynamic mixers are prone to producing a large quantity of oil droplets having a diameter of less than 10 micron, which is detrimental to the transport of oil-in-water emulsion(s) as such small oil droplet increase the viscosity of the oil-in-water emulsion(s), and can cause the oil-in-water emulsion(s) to invert from a water continuous emulsion into an oil continuous emulsion, with an attendant increase in viscosity. Dynamic mixers are also susceptible to high maintenance expense because of their use of high-speed rotating devices.
What is needed and what has been invented by us is a process for the preparation of stable water-continuous crude oil, or other hydrocarbon, transport emulsions, and which can generally form an emulsion having a water-continuous phase of any produced hydrocarbon crude, especially Athabasca bitumen (e.g. Syncrude bitumen) from the Athabasca tar sands in the province of Alberta, Canada.